OBJECTIVE To demonstrate that the development of progressive osteopenia in ovariectomized rhesus monkeys can be prevented by treatment with the potent bisphosphonate zoledronate. RESULTS Ovariectomy produced rapid bone loss of ~8% at the lumbar spine and total body. This was prevented in a dose-dependent fashion by zoledronate. This study was the most comprehensive assessment of estrogen depletion bone loss and the effect of a bisphosphonate compound on this loss in non-human primates. Elevated skeletal turnover was clearly demonstrated and was suppressed dose dependently by zoledronate. Biomechanical testing observed reduced bone strength following ovariectomy which was prevented by zoledronate. These results suggest that this compound will likely prove efficacious in the prevention and treatment of osteoporosis in postmenopausal women. FUTURE DIRECTIONS Quantitative histomorphometric assessment of samples from this study are pending. KEY WORDS osteoporosis, bisphosphonate, estrogen-depletion, bone density, bone strength FUNDING Novartis pharmaceuticals PUBLICATIONS Davidowitz, B. I., Banovetz, S., Boehm, K., & Binkley, N. 1998 Increased lead concentration in the drinking water of an animal care facility. AALAS Contemporary Topics in Animal Science 37:51-53. [J] Binkley, N., Kimmel, D., Bruner, J., Haffa, A., Davidowitz, B., Meng, C., Schaffer, V., Green, J. 1998 Zoledronate prevents the development of absolute osteopenia following ovariectomy in adult rhesus monkeys. J. Bone Miner Res. 13:1775-1782. [J]